Once destined to live eternally in landfills and landscapes, plastics are now getting second—and third and fourth—lives as recycled products that range from clothing to furniture. One of the newest reincarnations of discarded bottles and Tupperware: bridges. These plastic passageways are so strong they can support the weight of trucks, trains, and even tanks.

Working with Rutgers University engineers, New Jersey-based building supply company Axion International developed a nearly 100 percent recycled plastic mixture that has the strength of steel and concrete. “The combination is ingenious in its simplicity,” with No. 2 plastics like milk cartons and shampoo bottles and a few polymers like fiberglass being the only ingredients, says Jim Kerstein, the company’s cofounder and chief technology officer. The mixture is also nontoxic, he says, so it won’t release harmful chemicals into the environment.

Since 1998 Axion has built 10 bridges in the United States, from Maine to California, and more in Europe. One in Scotland stretches 90 feet across the River Tweed, and the company is currently consulting with engineers to create bridges with longer spans.

The effort offers a timely solution to an emerging problem. One in every nine U.S. highway bridges is “structurally deficient” and in desperate need of significant repair or replacement, according to a 2011 report by Transportation for America based on Federal Highway Administration data. That’s because most overpasses are built of wood, concrete, and metals, which rot and rust as they interact with the elements and fluctuating temperatures. Studies of plastic bridges showed no corrosion after 40 accelerated years, and unlike traditional structures that can take months to build, most plastic bridges come pre-made and require only days to link together like puzzle pieces.

With eco-friendly cars gaining popularity and old tires being incorporated into the very roads they once traveled, recycled bridges are just one more piece in the greening of America’s transportation sector.

This story originally ran in the May-June 2012 issue as "Heavy-Duty Tupperware."